This invention relates to radio frequency communication devices. More particularly, the invention relates to radio frequency identification devices for inventory control, object monitoring, determining the existence, location or movement of objects, or for remote automated payment.
As large numbers of objects are moved in inventory, product manufacturing, and merchandising operations, there is a continuous challenge to accurately monitor the location and flow of objects. Additionally, there is a continuing goal to interrogate the location of objects in an inexpensive and streamlined manner. One way of tracking objects is with an electronic identification system.
One presently available electronic identification system utilizes a magnetic coupling system. In some cases, the tag device may be provided with a unique identification code in order to distinguish between a number of different tags. Typically, the tag devices are entirely passive (have no power supply), which results in a small and portable package. However, this identification system is only capable of operation over a relatively short range, limited by the size of a magnetic field used to supply power to the tags and to communicate with the tags.
Another electronic identification system utilizes a large active transponder device affixed to an object to be monitored which receives a signal from an interrogator. The device receives the signal, then generates and transmits a responsive signal. The interrogation signal and the responsive signal are typically radio-frequency (RF) signals produced by an RF transmitter circuit. Because active devices have their own power sources, and do not need to be in close proximity to an interrogator or reader to receive power via magnetic coupling. Therefore, active transponder devices tend to be more suitable for applications requiring tracking of a tagged device that may not be in close proximity to an interrogator. For example, active transponder devices tend to be more suitable for inventory control or tracking.
Electronic identification systems can also be used for remote payment. For example, when a radio frequency identification device passes an interrogator at a toll booth, the toll booth can determine the identity of the radio frequency identification device, and thus of the owner of the device, and debit an account held by the owner for payment of toll or can receive a credit card number against which the toll can be charged. Similarly, remote payment is possible for a variety of other goods or services. An electronic identification system which can be used as a radio frequency identification device, and various applications for such devices are described in detail in commonly assigned U.S. patent application Ser. No. 08/705,043, filed Aug. 29, 1996, and incorporated herein by reference.
For active devices, battery drain is an important issue. The battery may be drained by spurious emissions of the necessary radiation to activate a radio frequency identification device. A power conservation problem is posed by such implementations where batteries are used to supply power to the circuitry of the radio frequency identification device. If the circuitry operates continuously at full power, battery life will be short, and device will have to be frequently replaced. If the battery is permanently sealed in a housing, replacement of the battery will be difficult or impossible. One reason for sealing the battery with the circuitry in a housing is to simplify the design and construction, to reduce the cost of production, and protect the electrical interconnections between devices. Another reason is protection of the battery and circuitry from moisture and contaminants. A third reason is to enhance the cosmetic appeal of the device by eliminating the need for an access port or door otherwise necessary to insert and remove the battery. When the battery is discharged, the entire device is then discarded. It is therefore desirable in such embodiments applications to employ power conservation techniques in order to extend useful life.
Additionally, for security control, a holder of an active or passive radio frequency identification device may want to prevent unwanted reading of the radio frequency identification device. One potential problem with existing radio frequency identification devices, particularly those with large communication ranges, is that the holder of the device may not have control over when the device is being interrogated. There are times when the holder would want the device to be interrogated, such as to authorize payment. On the other hand, there are other times when the holder would not want the device to be interrogated. For example, if the device is interrogated to seek payment for a particular service, another service provider who is related to or has a marketing deal with the first service provider may seek to solicit business from the holder when the holder enters the premises of the second service provider. There may be sensitive information on the device, such as health information, address information, purchase histories, credit information, that the holder would not want to have accessed without knowledge or approval.
Therefore, there is a need to provide a holder of a radio frequency identification device with the ability to control whether the device is interrogated.
The invention provides a wireless identification device including a housing, and circuitry in the housing configured to provide a signal to identify the device in response to an interrogation signal. A selectively actuated switch is supported by the housing and permits operation of the circuitry only while the switch is actuated.
In one aspect of the invention, the switch is a momentary switch.
One aspect of the invention provides a RFID device including a push button switch which allows the RFID device to become temporarily active. The user of the device has control over when the RFID device responds to an interrogator.
In one aspect of the invention, the switch is coupled to the power supply of an active RFID device, or a power supply receiver in a passive or magnetically coupled device. While the switch is pushed, the RFID device can be interrogated by a reader. In one embodiment, where the switch is coupled to the power supply, the device includes a non-volatile memory.
In one aspect of the invention, the switch sets a digital circuit flag in an active device to allow the device to operate momentarily. In another aspect of the invention, the switch sets a digital circuit flag in a passive device, when RF power is available, to allow the device to operate momentarily.
One embodiment of the invention provides a radio frequency identification device comprising an integrated circuit including a receiver, a transmitter, and a microprocessor. In one embodiment, the integrated circuit is a monolithic single die single metal layer integrated circuit including the receiver, the transmitter, and the microprocessor. The device of this embodiment includes an active transponder, instead of a transponder which relies on magnetic coupling for power, and therefore has a much greater range.
Another aspect of the invention provides a method of manufacturing a wireless identification device. Circuitry is configured to provide a signal to identify the device in response to an interrogation signal. The circuitry is coupled to a selectively actuated switch, such that the circuitry provides the signal only while the switch is actuated. The circuitry is encased in a housing such that the switch is actuable from outside the housing by touching a portion of the housing.